Lubricating oil compositions are employed in internal combustion engines. Various improvements have been made to lubricating oils intended for service in internal combustion engines, including the addition of various additive packages to base oils, the additive packages typically comprising one or more hydrocarbon-soluble ashless dispersants, corrosion inhibitors, anti-oxidants, friction modifiers, overbased sulfonate detergents, and anti-wear agents such as zinc dialkyldithiophosphates (ZDDP). The development of modern additive packages have significantly lengthened the service life of lubricating oils intended for service in internal combustion engines.